package com.hacker.highccy.service.Impl;

import com.hacker.highccy.dao.SeckillDao;
import com.hacker.highccy.dao.SuccessKilledDao;
import com.hacker.highccy.dto.Exposer;
import com.hacker.highccy.dto.SeckillExecution;
import com.hacker.highccy.entity.Seckill;
import com.hacker.highccy.entity.SuccessKilled;
import com.hacker.highccy.enums.SeckillStatsEnum;
import com.hacker.highccy.exception.RepeatKillException;
import com.hacker.highccy.exception.SeckillCloseException;
import com.hacker.highccy.exception.SeckillException;
import com.hacker.highccy.service.SeckillService;
import org.slf4j.LoggerFactory;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;
import org.springframework.transaction.annotation.Transactional;
import org.springframework.util.DigestUtils;

import java.util.Date;
import java.util.List;

/**
 * @Author:这个程序员有纹身
 * @Date: Created in 21:58 2017\12\26 0026
 */
//@Component  @Service   @Dao  @Controller
@Service
public class SeckillServiceImpl implements SeckillService{

    private org.slf4j.Logger logger = LoggerFactory.getLogger(this.getClass());
    //注入service依赖、Resource、@inject
    @Autowired
    private SeckillDao seckillDao;
    @Autowired
    private SuccessKilledDao successKilledDao;

    //md5盐值字符串，用于混淆MD5
    private final String slat = "asldkmnvq[osdnvlakwemfo1345-0asdfo140?:>}";

    public List<Seckill> getSeckillList() {
        return seckillDao.queryAll(0,4);
    }

    public Seckill getById(long seckillId) {
        return seckillDao.queryById(seckillId);
    }

    public Exposer exportSeckillUrl(long seckillId) {
        Seckill seckill = seckillDao.queryById(seckillId);
        if(seckill == null){
            return new Exposer(false,seckillId);
        }
        Date startTime = seckill.getStartTime();
        Date endTime = seckill.getEndTime();
        Date nowTime = new Date();
        if(nowTime.getTime() < startTime.getTime() || nowTime.getTime() > endTime.getTime()){
            return new Exposer(false,seckillId,nowTime.getTime(),startTime.getTime(),endTime.getTime());
        }
        //转化特定字符串的过程，不可逆
        String md5 = getMD5(seckillId);
        return new Exposer(true,md5,seckillId);
    }

    private String getMD5(long seckillId){
        String base = seckillId+"/"+slat;
        String md5 = DigestUtils.md5DigestAsHex(base.getBytes());
        return md5;
    }

    @Transactional
    /**
     * 使用注解控制事务方法的优点：
     * 1、开发团队达成一致约定，明确标注事务方法的编程风格
     * 2、保证事务方法的执行时间尽可能短，不要穿插其他的网络操作，RPC、HTTP请求、或者剥离到事务方法外部
     * 3、不是所有的方法都需要事务，如只有一条修改操作、只读操作，不需要事务控制
     */
    public SeckillExecution executeSeckill(long seckillId, long userPhone, String md5)
            throws SeckillException, RepeatKillException, SeckillCloseException {
        if (md5 == null || !md5.equals(getMD5(seckillId))) {
            throw new SeckillException("seckill data rewrite");
        }
        //執行秒殺逻辑：减库存 + 记录购买行为
        Date nowTime = new Date();

        try {
            //减库存
            int updateCount = seckillDao.reduceNumber(seckillId, nowTime);
            if (updateCount <= 0) {
                //没有更新到记录,秒杀结束
                throw new SeckillCloseException("seckill is closed");
            } else {
                //记录购买行为
                int insertCount = successKilledDao.insertSuccessKilled(seckillId, userPhone);
                //唯一验证
                if (insertCount <= 0) {
                    //重复秒杀
                    throw new RepeatKillException("seckill repeated");
                } else {
                    //秒杀成功
                    SuccessKilled successKilled = successKilledDao.queryByIdWithSeckill(seckillId, userPhone);
                    return new SeckillExecution(seckillId, SeckillStatsEnum.SUCCESS, successKilled);
                }
            }
        }catch (SeckillCloseException e1){
            throw e1;
        }catch (RepeatKillException e2){
            throw e2;
        }catch (Exception e) {
            logger.error(e.getMessage(), e);
            //所有编译期异常转为运行期异常
            throw new SeckillException("seckill inner error"+ e.getMessage());
        }
    }
}
